Patent GB-191329694-A (GB)
Title: Improvements in and relating to Steam Actuating and Distributing Valves for Direct-acting Pumps.
Filed: 1913-12-24
Granted: 1915-07-22
Abstract: 29,694. Weir, G. & J., Weir, W., and Peterm÷ller, J. Dec. 24. Combined fluid-actuated and mechanical gears; expansion valves. -Relates to valve arrangements of the type in which the steamthrown main-distribution slide valve has a central recess with a flat face on which slides a positively - actuated auxiliary valve adapted to control the flow of steam for throwing the main valve, the auxiliary valve or another valve being also adapted to cut off the steam supply to the main cylinder. The invention consists in forming the main valve as a piston valve with three pistons at each end adapted for throwing the valve and for controlling annular ports in the valve casing. In the form shown in Figs. 1, 2, 3, and 4. the main valve a has at each end pistons f, g, h, f<1>, g<1>, h<1> working over annular ports t, s, t', s', and the auxiliary valve b controls the flow of steam for throwing the main valve and cuts off the steam supply to the main cylinder. In the position shown, with the main piston and auxiliary valve at the top of their strokes, steam entering through the connexion d to the chamber 4 passes through the passages w<1>, 111, u<1>, s<1> to the upper side of the main piston. As the main piston descends, it moves downwards the auxiliary valve which will first cover the port w<1> and cut off the steam from the upper side of the main piston; then, to throw the main valve, admit steam through the passages v<1>, 101 to the chamber q<1>, and establish communication between the chamber q and the exhaust c through the passages 10, v, m in the face of the auxiliary valve j, 12, r<1>, t<1>; and also uncover the port w so that, when the main valve has been thrown over, steam is admitted to the lower side of the piston from the chamber 4 through the passages w, 11, u, s. Manuallycontrolled valves mav be employed to supply additional steam during either stroke when required. The main valve may be modified by interchanging the functions of the spaces between the middle and inner pistons and the middle and outer pistons. The auxiliary valve may be replaced by two valves which work on parallel faces of the main valve, one auxiliary valve serving to control the flow of steam for throwing the main valve, and the other auxiliary valve acting as a cut-off valve for the steam supply to the main cylinder. In the modification shown in Figs. 11 and 13, the piston cut-off valve 13, 14 is separate from the flat auxiliary valve b. When the auxiliary valve b moves upwards from its lowest position, it uncovers the port v<1> to allow steam to pass from the chamber 4 to the chamber q<1>, and also places the chamber q in communication with the exhaust through the passages 10, v, m in the face of the auxiliary valve j, 12, t, e to throw the main valve. The cut-off valve consists of two adjustable pistons 13, 14 and is carried on the rod 2 of the auxiliary valve. When the cut-off valve is in its lowest position, steam passes from the chambers 40, 4 through the passages 15, x, u, s to one side of the main piston, steam from the other side passing through the passages s<1>, u<1>, t<1> to exhaust. When the cut-off valve rises, it closes the passage 15 and cuts off the steam supply to the main cylinder. In the modification, shown in Fig. 17, the cut-off valve, formed of three pistons 21, 22, 23, and the auxiliary valve b are on separate spindles.